The present invention relates to stabilization of radio frequency quadrupoles, and more particularly, it relates to stabilization of a radio frequency quadrupole that includes vanes such as used for accelerating charged particles.
Radio frequency quadrupole (RFQ) devices have a number of uses. One such use is as a charged particle accelerator which is especially useful for ion implantation, nuclear medicine, fusion research, and, in general, any work requiring low and medium energy ions. RFQ devices are simple and convenient to use as accelerators since charged particles, in particular low-beta ions, may be simulataneously bunched, focused and accelerated. However, in order to be fully useful as a practical particle accelerator, an RFQ device should be reliable, easy to tune and drive, and dependable in its frequency and mode characteristics; and beam loading due to high currents should not cause severe unbalance of the quadrant fields of an RFQ device.
The general design of an RFQ particle accelerator known in the art is shown and described in a paper by Hansborough, Potter and Wilson in "Mechanical Design of RFQ Resonator Cavities In The 400-MHz Frequency Range", Los Alamos National Laboratory, Los Alamos, N. Mex. 87545, February 1982, and incorporated herein by reference. In this paper, some basic tuning methods of an RFQ accelerator are discussed. It will be noted, however, that these methods require complex mechanisms and that the RFQ cavities, often require frequent tuning due primarily to relative mechanical shifting of the cavity parts such as results from thermal effects during construction and operation.